Switch assembly for a telephone subset



March 11, 1958 J. F. KESSLER SWITCH ASSEMBLY FOR'A TELEPHONE SUBSET Filed Nov. 14, 1956 INVENTOR. JAMES F. KESSLER AGE Unit

My invention relates to telephone subsets and more particularly to telephone subsets having manually operable auxiliary contact sets in addition to the conventional hookswitch contact sets.

In the past, it has been the practice to provide an auxiliary contact set on a telephone subset for such purposes as cutting off extension stations, thereby insuring against the possibility of intrusion while the subset is in use. An example of such a subset is found in Patent 2,273,530 Qing, where the auxiliary hookswitch actuating plunger is so positioned on the subset that the plunger engages the handset when the latter is on the subset cradle in the normal, on-hook position. Such an arrangement is advantageous because it insures the restoration of the auxiliary contact set to its normal condition when the subset is not in use. For this reason it is desirable to preserve the handset-actuated feature of such auxiliary contact set plunger. However, in telephone subsets of the type shown in Patent 2,749,395, entitled Telephone Subset, Droel and Kucharski, issued June 5, 1956, where the main body of the hookswitch assembly is laterally removed from the cradle pieces by a substantial distance, the control of auxiliary contacts by a plunger of the type taught by King becomes impractical if the practice of mounting auxiliary contact sets on the central bracket in the manner disclosed by Droel and Kucharski is to be followed.

Accordingly, it is an object of my invention to provide a new and improved auxiliary contact set mounting method.

Another object of my invention is to provide a new and improved method for actuating such auxiliary contact sets.

Another object of my invention is to provide an auxiliary contact set which may be included or omitted from a particular subset without modifying the hookswitch assembly.

I accomplish these and other objects in the manner described in the following paragraphs. For a better understanding of my invention, reference is made in the following paragraphs to the drawings attached to and forming a part of the present specification, and in which:

Fig. 1 shows a partial view of an assembled telephone subset;

Fig. 2 shows a cross-section taken through a part of the assembled subset; and

Fig. 3 shows a partially exploded view of a cradle and plunger piece bearing an auxiliary contact set.

Referring to Fig. 1, my invention may be practiced in a telephone subset of the type described in the aforementioned Droel and Kucharski patent. The subset comprises a pedestal portion including shell 1 and a handset including transmitter portion 5, receiver portion 6, and the handle portion 7 which interconnects portions and 6. The pedestal portion also includes base 2 on which the support 12 is fixed. Hookswitch contact set 9 is secured to support 12 by screws such as 11. The contact bearing end of the hookswitch contact springs within set 9 are controlled by U-shaped hookswitch arm 5 which is pivotally attached to bracket 12 by pin 6. Arm 13, which is also fixed to base 12 by the contact set securing screws such as 11, carries one end of biasing spring 10. The other end of spring is attached to arm 5 so that spring 1E3 urges arm 5 in an upper direction around pivot pin 6.

2,826,645 Patented Mar. 11, 1958 Combined cradle and plunger pieces 4 and 4a are pivotally attached to the ends of the legs of arm 5 by a pin such as 8. The upper, handset-receiving portions of the plunger pieces including surfaces 14 and 14a emerge through openings in shell 1 when the latter is in its assembled position on base 2 in the manner shown inFig. 2. While the subset is not in use, portion 7 of the handset is laid across surfaces 14- and 14a of the plunger pieces. The weight of the handset is sufficient to overcome the tension in biasing spring 10, so that the current plunger pieces depress arm 5 which in turn causes contact set 9 to assume its normal position. When the handset is removed from cradle pieces 4 and 4a, the tension in biasing spring 10 moves arm 5' in an upward direction for a distance sufiicient to operate the springs in contact set 9.

The present invention relates to the mounting of and apparatus for operating an auxiliary contact set. The auxiliary contact set includes springs such as 15 and 15a mounted on one of the plunger pieces such as 4. At the end of mounting the auxiliary contact set, grooves of rectangular cross-section are formed on opposite sides of the plunger piece 4. The grooves, of uniform depth, follow a nonlinear path across the sides of the plunger piece and are parallel to each other throughout their length. One end of each groove terminates at an edge of the plunger piece 4. The other end of the groove terminates in an edge of plunger piece 4 formed at an opening or window 40 passing through plunger piece 4 from one side surface to the other. Both the groove and window are so positioned on plunger piece 4 that they lie entirely within the shell 1 when plunger piece 4 is in its raised (operated) position. The springs such as 15 and 15a which are included in the auxiliary contact set are substantially the same width as the grooves and are shaped along a portion of their length to be received within the grooves. Of the remaining portions of each spring, one end emerges from the block to receive an externally connected wire or wires such as 24a or 24b while the other end lies Wholly within the aforementioned window. The end lying within the window is offset from the remainder of the spring toward the center of plunger piece 4 and bears a contact such as 16.

The depth of the groove in the sides of plunger piece 4 is sufficient to allow the outward-facing surfaces of the springs 15 and 15a as well as the presently described fastening means and plunger assembly to lie wholly within the boundaries of the plunger piece 4 defined by the side surfaces of the plunger piece. The springs are secured to plunger piece 4 (which is made of insulating material) by a single fastening means including fiber insulator 2t Insulator 20 is inserted through an aperture passing through plunger piece 4 and which intersects the bottom of the spring-receiving grooves. Insulator 2t) also passes through corresponding openings in springs 15 and 15a. Screw 21 is then inserted through insulator 20. The springs are further insulated from each other by placing fiber washer 22 over the threaded end of screw 21 and insulator 20. The contact assembly is then fixed in position by running nut 23 onto the threaded portion of the screw.

By making the groove and spring widths substantially equal it is possible to fix the springs relative to each other so that the contacts 16 of each spring engage when the springs are deflected inwardly, in the manner to be described, by the use of the above-described single fastening. The use of nonlinear spring-receiving grooves in cradle piece 4 prevents interference between plunger piece 4 and shell 1 at the straight, thin wall formed in shell 1 at the plunger piece receiving aperture because atleast a portion of each side surface of the plunger 4- is presented to the aforementioned thin wall of the shell as the plunger piece is passed through the aperture during the assembly of the subset.

A plunger assembly including actuating plunger .18 is provided for controlling the auxiliary contact set. Plunger 18 passes-through vertical openings in cradle piece 4 and between springs and 15a. A-n enlarged, insulated cam portion 17 is fixed to plunger 18. When plunger 18 is in its normal, depressed position, the rounded lower section of portion 17 engages springs 15 and 15a forcing them apart, so that the contacts 16 of springs 15 and 15a are disengaged from each other. As will be described, plunger 18 may be manually raised to disengage portion 17 from springs 15 and 15a so that tension within springs 15 and 15a causes the springs to be deflected toward the center of plunger piece 4. Thus contacts 16 of the auxiliary springs engage when plunger 18 is raised to its operated position. While I show a single set of make-break contacts as the preferred embodiment of my invention, it will be understood by those skilled in the art that it is possible to provide spring combinations of more than one setand type by modifying the above-described structure.

In order to make it possible for plunger 18 to be manuaily operated, a handle portion 19 is fixed to the upper end of plunger 18. When plunger 18 is in its normal or lower position, handle 19 lies partially within a recess in surface 14 of plunger piece 4, and is depressed below surface 14 for a distance sufficient to make the upper surface of handle 19 substantially coplanar with the handsetreceiving surface 14. Thus, with plunger 18 in normal position, the handset may be placed in the plunger piece without interfering with the position of the handleportion 19. The recess in which the handleportion is depressed opens into the sides of plunger piece 4. Handle,

portion 19 is of sufiicient' Width to overhang the side surfaces of plunger piece 4. The user of the subsetmay therefore grasp the overhanging portions of plunger handie 19 between his thumb and forefinger to manually raise the plunger 18 from the normal lower position. When plunger 18 is'in its raised or operated position, theweight of the handset, when placed on handle portion 19, is sufiicienttocause enlarged portion 17 to force apart springs 15 and 15a, so that handle 19 and plunger-1d canagain be restored to their-normal lower positions when the handset is hung up. In this manner, the aforementioned-restoration of the auxiliary contactset to its normal condition when the subset is not in use is accomplished. V

While I have shown and described a particular embodiment of my invention, it will be. obvious to those skilled in the art that changes and modifications may be made without departing from my invention in its broader aspect. all such changes and modifications as fall within the true spirit and scope of my invention.

What is claimed is:

1. In a contact assembly for use in a telephone subset, a plunger piece comprising a block of insulating material for receiving a telephone handset, said block having sides and an opening passing through said block from one of said sides to the other, a set of contact springscarried by said block, a portion'ofeach of saidsprings extending into said opening, and means for actuating said spring set, said spring portions and said actuating means lying wholly within borders of said block defined by said walls,

whereby said springportions andv saidactuating means are non-interfering withother components in said subset which are adjacent tosaid sides,

2. The contact assembly setforth in clainr lj wherein grooves in said sidesterminate insaid opening, and having in addition certainother portions .of each ofsaid springs received within, said grooves, said certainother portions lying wholly within the boundaries of said block defined by said side'surfaces.

3.-The=contact' assembly set forth in claim 1 wherein I, therefore, intend in the appended claims-to cover grooves in said sides having a rectangular cross-section terminate in said opening, and having in addition certain other portions of each of said springs of rectangular crosssection and of substantially the same width assaid grooves,

tersecting the bottoms of saidgrooves for securing said l springs, whereby said single. fastening means is effective for preventing lateral, movements of said springs and said springs are restrained. against rotational movement rela tive to said block and each other; by the wallsv of said grooves.

5. The contactassembly [set forth in claim '1 wherein grooves insaid sides substantially parallel throughout their lengthfollow a curved path across a part of said sides and terminate in said opening,.and,certain other portions of each ofsaidsprings received within said grooves,- said certain other portions lying wholly within the boundaries of said block definedby said surfaces, whereby interference'between said grooves ,and narrow straight line'surfaces within said :subset which areadjacent to said plunger piece do not. interfere with said grooves as said plungerpiece is;moved with respect to the straight line narrow surfaces,

6. 'In a; telephone subset comprising a shell, a hookswitch assembly including a contact set within said shell, a combined cradle-plunger piece'attachedto said hookswitch assembly for actuating said contact set, and a'hand-. set, wherein a portion ofsaid plunger piece emerges from,

certain other portions of each of said springs received Within said grooves, said certain other portions lying wholly within boundaries of said block defined by said sides, and single fastening means passing through a third opening through said block intersecting the. bottoms of each of said grooves for securing said springs to said plunger piece, whereby said spring portions and said actuating means are non-interfering with other components in said subset which are mounted adjacent to said sides and narrow straight surfaces of apparatus mounted adjacent to said sides are non-interfering with said plunger piece as said plunger piece ismoved vertically to operate said hookswitch assembly.

7. In a contact assembly for use in a telephone subset, a plunger piece comprising a block of insulating material for receiving a telephone handset, said block having sides and a top surface-,a set of contact springs carried by said block, means including aplunger and a manually operable handle secured to saidplunger for operating said contact set, said plunger passing through an opening insaid blockwhich intersects said top surface, a recess within said top surface for receiving said handle, said handle being of substantially greater width than the width of said block, whereby the top of said handle is substantially coplanar with said top surface when said plunger is depressed and said handle overhangs said side surfaces in order to facilitate manual operation of said contact operating means.

No references cited. 

